On Power Consumption Estimation and Power Distribution Profiling for VLSI Circuit

• Main Authors: Heng-Liang Huang, 黃恆亮
• Other Authors: Jing-Yang Jou
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/w4rc4t

博士 === 國立交通大學 === 電子工程系所 === 92 === As the semiconductor technology getting advances, the density of the devices and the metal lines are growing too large to keep the heat conduction problem unnoticed. Furthermore, the heat generated by the circuits is boosted with the ramping of the operating speed. Improperly heat conduction can lead to the smoking of the chip, torturing or breaking of the metal lines, or shifting of the performance. All these problems can be prevented by the power consumption estimation and optimization before taping out the chip. There are many ways of estimating power corresponding to different purposes. For example, we need to estimate energy consumption for battery endurance, we need the power consumption for temperature analysis, and we need the average current for wire width design, and the current density for reliability analysis. Although these measurements are all clearly defined, but they have a common problem that they are input signal dependent. To do the power analysis without lost of generality, we propose an automatic power profiler which is integrated into the most accurate circuit simulator - SPICE. With the power profiler, users can get a visual figure of the power consumption distribution instead of numbers with uncertainties. In this dissertation, we first analyze the relation between input statistics and the power consumption of the integrated circuits. The power sensitivities of inputs are proven to be effective provided the nominal points are selected properly. With this acknowledge, the power sensitivity sum of each input can be used to indicate the power consumption tendency of the input vectors, and to stratify the input vectors with. After the stratification, the sample variance can be reduced when simulating the input vectors selective. In addition, we found that stratification with power sensitivity can prevent the pre-matured estimation when estimating the average power consumption with Monte Carlo method. We also proposed a new way of stratification that is suitable for stratifying infinite length input sequences based on POST and POSTIV. By putting these findings together, we have modified the SPICE circuit simulator to be a tool that can visualize the distribution of the power consumption according to the user specified input statistics or input sequences.